What is the product obtained when orthophosphoric acid $(H_3PO_4)$ is heated to a high temperature?

What are the number of $P - O - P$ bridges in phosphorus pentoxide $(P_4O_{10})$ and phosphorus trioxide $(P_4O_6)$ respectively?

Write the main differences between the properties of white phosphorus and red phosphorus.

Give an example to show the effect of concentration of nitric acid on the formation of oxidation products.

Given below are the two statements: one is labeled as Assertion $(A)$ and the other is labeled as Reason $(R)$.
Assertion $(A)$: There is a considerable increase in covalent radius from $N$ to $P$. However,from $As$ to $Bi$,only a small increase in covalent radius is observed.
Reason $(R)$: Covalent and ionic radii in a particular oxidation state increase down the group.
In the light of the above statements,choose the most appropriate answer from the options given below:

$P_2O_3 + H_2O \rightarrow X$
$Red \ P_4 + \text{alkali} \rightarrow Y$
$X$ and $Y$ are oxoacids of phosphorus. The number of $P-OH$ bonds in $X$ and $Y$ respectively is: